In the field of turbomachines, and in particular aircraft turbomachines, it may prove necessary to provide means for discharging fluids of different natures, for example such as gas, oil or water, and in particular flammable fluid residues. Such a discharge of these fluids may for example be possible to prevent them from accumulating and disrupting the operation of the turbomachines. For example, some turbomachines require bleed operations that cause fluid losses that must be recovered and treated. Furthermore, such drainage is especially necessary in the case of flammable fluids so as to prevent a fire in the turbomachines.
Several solutions are already known to allow the discharge by drainage of fluids contained in a turbomachine enclosure. Preferably, the drainage of fluids is thus done at a low point of the turbomachine, in particular a low point of the enclosure. “Low point” refers to the point radially furthest from the axis of the turbomachine. To that end, the existing traditional solutions, to establish a bleed at a low point of a turbomachine enclosure, most often consist of forming drainage means on a casing of the enclosure, in particular by piercing and machining the casing to form one or more discharge orifices.
As an example, FIG. 1 diagrammatically and partially shows an example of the formation of drainage means 20a and 20b, at the low point of a line of casings of a high-pressure compressor 21 and a combustion chamber 22 of a turbomachine. In this FIG. 1, the high-pressure compressor 21 and the drainage means 20a and 20b have been very diagrammatically shown using blocks for simplification reasons.
The combustion chamber 22 comprises an annular flame tube 23, delimited by an inner shroud 24 and an outer shroud 25 concentric to the latter part, and comprising a chamber bottom 26 in the form of a plate passed through by the injectors 27 supplied by injection conduits 28. A compressor nozzle 29 provides the compressed air used for operation of the turbomachine by supplying a diffusion chamber 30 in which the flame tube 23 is submerged. Furthermore, as can be seen in this FIG. 1, the rear casing 2 of the high-pressure compressor 21 and the chamber casing 3 of the combustion chamber 22 are assembled to one another, by upstream 4 and downstream 5 flange parts, respectively.
In order to ensure the discharge of any fluid residues located in the enclosure formed by the rear casing 2 of the high-pressure compressor 21 and the chamber casing 3 of the combustion chamber 22, drainage means 20a and/or 20b can respectively be provided on the rear casing 2 of the high-pressure compressor 21 and on the chamber casing 3 of the combustion chamber 22. These drainage means 20a, 20b must preferably be formed at the low point of the line of casings formed by the rear casing 2 and the chamber casing 3 to facilitate the drainage, in other words, in a lowest region of the line of casings, i.e., also at the point radially furthest from the axis T of the turbomachine. It is thus provided to pierce and machine the rear casing 2 to form the drainage means 20a, and to pierce and machine the chamber casing 3 to form the drainage means 20b. 
Nevertheless, the solutions of the prior art are not fully satisfactory and have several drawbacks. In fact, the formation of the drainage means on the casings of the turbomachine may have a substantial negative impact on the performance of the turbomachine. In particular, it may prove difficult to truly form drainage zones at the low point of the line of casings, which prevents obtaining optimal drainage of the fluids. Furthermore, being positioned on the casings of the turbomachine causes many constraints in producing the drainage means, and in particular in terms of mass increase, decreased lifetime of the parts, and machining difficulties to form the drainage orifices.